1. Field of the Invention
The present invention relates to a composition containing silico-organic nanohybrid and/or microhybrid capsules for scratch-resistant and/or abrasion-resistant coatings, wherein the silico-organic nanohybrid and/or microhybrid system includes one or more small metal oxide cores A and a substantially complete, silico-organic shell B, and the composition can be obtained by a reaction performed in situ, in a synthetic resin or in a synthetic-resin precursor compound, between metal oxide particles (KA-O) and at least one organofunctional silicon compound which contains an organofunctional group and at least one hydrolyzable group or at least one hydroxy group. The present invention also relates to the use of such compositions as the base for lacquers for producing a scratch-resistant and abrasion-resistant coating on a substrate as well as articles provided with corresponding scratch-resistant as well as abrasion-resistant coatings.
2. Discussion of the Background
The surface characteristics of sol or gel particles or of metal or semimetal oxides can be modified by treatment with a hydrolyzable organosilane or organosiloxane, wherein a single-layer silane coating is usually bound to the oxide or solgel particles. Oxides or sol or gel particles treated in this way, such as inorganic pigments or fillers, can be incorporated in a polymer matrixxe2x80x94in sheetings as well as in coating agents and coatings that can be produced therewith. Usually, however, the scratch resistance and abrasion resistance of such polymer systems is poor.
German Patent 19846660 discloses nanoscale, surface-modified oxide and mixed oxide particles enveloped by silico-organic groups bonded covalently to the oxide particle, wherein the organofunctional groups are described as reactive groups and are usually oriented outward, so that, during curing of the prepolymer, they become incorporated in the polymer matrix by polymerization with the polymeric material. The method for preparation of such coating agents is complex, since the organosilane and the oxide components are incorporated in alternating sequence in the prepolymer.
German Patent 19846659 has the same priority date as German Patent 19846660 and relates to a layered material, which is provided with a scratch-resistant synthetic-resin layer that also contains nanoscale, surface-modified oxide particles. German Patent 19846659 discloses the use of acryloxyalkylsilanes for production of a shell of nanoscale oxide particles containing reactive groups capable of radiation cross-linking. Here also the preparation of the coating agent takes place by a time consuming reaction of a nanoscale silica with 3-methacryloxypropyltrimethoxysilane (DYNASYLAN(copyright) MEMO) in an acrylate formulation in the presence of water, an acid and a surfactant. The components must be brought together in a special alternating sequence.
Hydrolyzable silane components having ethylenically unsaturated organic groups are expensive starting materials. In addition, DYNASYLAN(copyright) MEMO tends to react in the presence of minor traces of substances capable of initiating polymerization or in the presence of radiation, whereby the viscosity of a corresponding formulation can increase drastically. Stabilizers must be added to prevent the undesired polymerization. Thus it is often difficult to control the manipulation of the starting materials and the preparation of such coating systems.
In addition, the above-mentioned coating agents are frequently highly viscous and usually contain only a low proportion of oxide particles, with consequences for the scratch resistance of the subsequent coating. It is also difficult to apply such highly viscous coating agents onto a substrate, and this is particularly so in the case of thin substrates that are susceptible to tearing. The scratch resistance of coatings obtained in this way is often in need of improvement. Moreover, a special complex applicator is necessary for such highly viscous systems. Frequently, solvents are also added to such highly viscous coating agents, thus leading to increased organic emissions (the so-called, xe2x80x9cVOC problemxe2x80x9d, where VOC=volatile organic compounds).
In a Taber Abraser test performed per DIN 68861 (incorporated herein by reference) on a commercial abrasion-resistant PU lacquer, 2 mg of abraded material was measured after 50 revolutions.
According to German Patent Applications 10100631 and 10100633, which have not yet been published, substantially scratch-resistant (DIN 53799, incorporated herein by reference) coatings can be produced. Unfortunately, such coating systems cannot be used for applications in which not only scratch resistance but also adequate abrasion resistance is necessary (haze according to DIN 52347/ASTM D-1044 {incorporated herein by reference} and abrasion according to DIN 68861, already incorporated herein by reference), for example for wood lacquers and for plastic and parquet floors. In addition, highly filled systems may exhibit in homogeneities, with disadvantages for the surface quality of the subsequent coating. At this place it is also appropriate to mention German Patent Application 10141690, which is entitled xe2x80x9cComposition containing silico-organic nanohybrid/microhybrid systems for scratch-resistant and abrasion-resistant coatingsxe2x80x9d.
One object of the present invention is to avoid the problems of the conventional compositions.
Another object of the present invention is to provide a composition suitable for use in lacquer formulations, scratch-resistant or abrasion-resistant finishes, which is homogeneous and which can be used in a wide variety of applications.
These and other objects have been achieved by the present invention, the first embodiment of which is a filled composition, which includes:
at least one silico-organic nanohybrid or microhybrid capsule; and
at least one synthetic resin or synthetic-resin precursor compound;
wherein the silico-organic nanohybrid or microhybrid capsule includes an oxide core A and a silico-organic shell B;
wherein the oxide core A includes at least one nanoscale or microscale particle (KA-O) of component (a), (b), or a mixture thereof,
wherein the (KA-O) component (a) includes at least one nanoscale oxide or mixed oxide of at least one metal or semimetal selected from the group including main groups 2 to 6 of the Periodic Table, transition groups 1 to 8 of the Periodic Table, lanthanides, and mixtures thereof;
wherein the (KA-O) component (b) includes at least one microscale corundum;
wherein the silico-organic shell B includes:
at least one silico-organic compound having the formula Ia:
(Sixe2x80x2Oxe2x80x94)xSixe2x80x94Rxe2x80x83xe2x80x83(Ia)
wherein R denotes an organofunctional group selected from the group including straight-chain, branched or cyclic alkyl group with 1 to 50 C atoms, alkenyl group with 2 to 6 C atoms, chloroalkyl, isocyanoalkyl, cyanoalkyl, fluoroalkyl, aryl, acylalkyl, acryloxyalkyl, methacryloxyalkyl, polysulfanealkyl, mercaptoalkyl, thiacyamidoalkyl, glycidyloxyalkyl, aminoalkyl, diaminoalkyl, triaminoalkyl, carbonatoalkyl and ureidoalkyl;
wherein x is a number from 0 to 20,
wherein remaining free valences of Si are each independently (KA-O)xe2x80x94, SiOxe2x80x94 or -Z,
wherein remaining free valences of Sixe2x80x2 are each independently (KA-O)xe2x80x94, SiOxe2x80x94, xe2x80x94R, or -Z,
wherein the Z groups are the same or different and denote hydroxy or alkoxy group, and wherein each Si or Sixe2x80x2 in the shell B have not more than one xe2x80x94R attached thereto;
which is obtained by reaction of:
(i) one or more oxide particles selected from the group including:
(a) at least one nanoscale oxide and/or mixed oxide of at least one metal or semimetal of the second to sixth main group or of the first to eighth subgroup of the periodic table or of the lanthanides or
(b) a microscale corundum; and
(c) a mixture of oxide particles of (a) and (b);
with
(ii) at least one organofunctional silane having the formula II:
R1sR2rSiY(4-s-r)xe2x80x83xe2x80x83(II),
wherein the groups R1 and R2 are the same or different and each represents a straight-chain, branched or cyclic alkyl group with 1 to 50 C atoms, an alkenyl group with 2 to 6 C atoms, a chloroalkyl, isocyanoalkyl, cyanoalkyl, fluoroalkyl, aryl, acylalkyl, acryloxyalkyl, methacryloxyalkyl, polysulfanealkyl, mercaptoalkyl, thiacyamidoalkyl, glycidyloxyalkyl, aminoalkyl, diaminoalkyl, triaminoalkyl, carbonatoalkyl or ureidoalkyl group, Y represents a methoxy, ethoxy, i-propoxy, n-propoxy or 2-methoxyethoxy group,
wherein s is equal to 1 or 2 or 3,
wherein r is equal to 0 or 1 or 2, with the proviso that (s+r)xe2x89xa63;
(iii) optionally a monomeric and/or oligomeric silicic acid ester, which is substituted with one or more methoxy, ethoxy, n-propoxy or i-propoxy groups and which has an average degree of oligomerization of 1 to 50;
and
(iv) optionally an organofunctional siloxane having one or more functionalities which are the same or different and each Si atom in the siloxane is substituted with one or more functionality selected from the group including alkyl, fluoroalkyl, cyanoalkyl, isocyanoalkyl, alkenyl, aminoalkyl, diaminoalkyl, triaminoalkyl, alkoxyalkyl, hydroxyalkyl, acylalkyl, glycidyloxyalkyl, acryloxyalkyl, methacryloxyalkyl, mercaptoalkyl, ureidoalkyl, aryl and alkoxy, and remaining free valences of each Si atom in the siloxane are independently saturated by one or more methoxy or ethoxy or hydroxy groups;
wherein the reaction is performed in situ in a liquid, curable synthetic resin or a precursor stage of a synthetic resin in which the content of oxide particles of component (i) is 10 to 300 parts by weight relative to 100 parts by weight of the synthetic resin component used, and the reaction is performed in a kneading or dispersing machine.
Another embodiment of the invention provides a method for preparing the above composition, which includes:
reacting:
(i) oxide particles from the series selected from the group including:
(a) at least one nanoscale oxide and/or mixed oxide particle of at least one metal or semimetal of the second to sixth main group or of the first to eighth subgroup of the periodic table or of the lanthanides or
(b) a microscale corundum particle or
(c) a mixture of oxide particles of (a) and (b),
with
(ii) at least one organofunctional silane having the formula II
R1sR2rSiY(4-s-r)xe2x80x83xe2x80x83(II),
wherein the groups R1 and R2 are the same or different and each independently represents a straight-chain, branched or cyclic alkyl group with 1 to 50 C atoms, an alkenyl group with 2 to 6 C atoms, a chloroalkyl, isocyanoalkyl, cyanoalkyl, fluoroalkyl, aryl, acylalkyl, acryloxyalkyl, methacryloxyalkyl, polysulfanealkyl, mercaptoalkyl, thiacyamidoalkyl, glycidyloxyalkyl, aminoalkyl, diaminoalkyl, triaminoalkyl, carbonatoalkyl and ureidoalkyl group,
wherein Y represents a methoxy, ethoxy, i-propoxy, n-propoxy or 2-methoxyethoxy group,
wherein s is equal to 1 or 2 or 3 and r is equal to 0 or 1 or 2, with the proviso that (s+r)xe2x89xa63,
and
(iii) optionally a monomeric and/or oligomeric silicic acid ester, which is substituted with one or more methoxy, ethoxy, n-propoxy or i-propoxy groups and which has an average degree of oligomerization of 1 to 50;
and
(iv) optionally an organofunctional siloxane having one or more functionalities which are the same or different and each Si atom in the siloxane is substituted with one or more functionality selected from the group including alkyl, fluoroalkyl, cyanoalkyl, isocyanoalkyl, alkenyl, aminoalkyl, diaminoalkyl, triaminoalkyl, alkoxyalkyl, hydroxyalkyl, acylalkyl, glycidyloxyalkyl, acryloxyalkyl, methacryloxyalkyl, mercaptoalkyl, ureidoalkyl, aryl and alkoxy, and remaining free valences of each Si atom in the siloxane are independently saturated by one or more methoxy or ethoxy or hydroxy groups;
wherein the reaction is performed in situ in a liquid, curable synthetic resin or a precursor stage of a synthetic resin in which the content of oxide particles of component (i) is 10 to 300 parts by weight relative to 100 parts by weight of the synthetic resin component used, and the reaction is performed in a kneading or dispersing machine.
Another embodiment of the invention provides a lacquer or scratch-resistant coating, which includes the above composition.
Another embodiment of the invention provides a method for making a lacquer or scratch-resistant coating, which includes contacting the above composition with a solvent.
Another embodiment of the invention provides a method for making a lacquer or scratch-resistant coating, which includes diluting the above composition with at least one selected from the group including a liquid synthetic resin, a precursor compound of a synthetic resin, a solvent, and mixtures thereof.
Another embodiment of the invention provides a method for making a coating, which includes contacting the above composition with a substrate.